Segment Information and Geographic Area Information - Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 30, 2016	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015	Apr. 29, 2017	Apr. 30, 2016	May 02, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 219.7	$ 195.6	$ 209.3	$ 191.9	$ 212.8	$ 184.6	$ 208.4	$ 203.3	$ 816.5	$ 809.1	$ 881.1
Property, plant and equipment	90.6				93.0				90.6	93.0	93.3
U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									506.9	491.9	564.6
Property, plant and equipment	44.9				44.0				44.9	44.0	42.7
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									127.7	124.8	112.6
Property, plant and equipment	5.9				7.4				5.9	7.4	9.0
Malta
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									155.5	167.1	153.5
Property, plant and equipment	26.4				28.7				26.4	28.7	28.0
Mexico
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment	4.3				3.9				4.3	3.9	5.8
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									26.4	25.3	50.4
Property, plant and equipment	$ 9.1				$ 9.0				$ 9.1	$ 9.0	$ 7.8